tests/dicts_tests.bzl

# Copyright 2017 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Unit tests for dicts.bzl."""

load("//:lib.bzl", "dicts", "asserts", "unittest")


def _add_test(ctx):
  """Unit tests for dicts.add."""
  env = unittest.begin(ctx)

  # Test zero- and one-argument behavior.
  asserts.equals(env, {}, dicts.add())
  asserts.equals(env, {"a": 1}, dicts.add({"a": 1}))

  # Test simple two-argument behavior.
  asserts.equals(env, {"a": 1, "b": 2}, dicts.add({"a": 1}, {"b": 2}))

  # Test simple more-than-two-argument behavior.
  asserts.equals(env, {"a": 1, "b": 2, "c": 3, "d": 4},
                 dicts.add({"a": 1}, {"b": 2}, {"c": 3}, {"d": 4}))

  # Test same-key overriding.
  asserts.equals(env, {"a": 100}, dicts.add({"a": 1}, {"a": 100}))
  asserts.equals(env, {"a": 10}, dicts.add({"a": 1}, {"a": 100}, {"a": 10}))
  asserts.equals(env, {"a": 100, "b": 10},
                 dicts.add({"a": 1}, {"a": 100}, {"b": 10}))
  asserts.equals(env, {"a": 10}, dicts.add({"a": 1}, {}, {"a": 10}))
  asserts.equals(env, {"a": 10, "b": 5},
                 dicts.add({"a": 1}, {"a": 10, "b": 5}))

  # Test some other boundary cases.
  asserts.equals(env, {"a": 1}, dicts.add({"a": 1}, {}))

  # Since dictionaries are passed around by reference, make sure that the
  # result of dicts.add is always a *copy* by modifying it afterwards and
  # ensuring that the original argument doesn't also reflect the change. We do
  # this to protect against someone who might attempt to optimize the function
  # by returning the argument itself in the one-argument case.
  original = {"a": 1}
  result = dicts.add(original)
  result["a"] = 2
  asserts.equals(env, 1, original["a"])

  unittest.end(env)

add_test = unittest.make(_add_test)


def dicts_test_suite():
  """Creates the test targets and test suite for dicts.bzl tests."""
  unittest.suite(
      "dicts_tests",
      add_test,
  )